1. Field
Various embodiments of the present invention relate to a memory device, and more particularly, to signal lines of a plurality of memory regions included in a memory device.
2. Description of the Related Art
Generally, a memory device may be either a volatile memory device or a nonvolatile memory device.
A volatile memory device has high write and read speeds, but loses data stored therein when power is turned or cut off. Examples of a volatile memory device include a dynamic random access memory (DRAM), and a static RAM (SRAM). On the other hand, a nonvolatile memory device has comparatively low write and read speeds, but retains data stored therein even when power is cut off. Therefore, a nonvolatile memory device is used when there is a need for storing data which should be retained regardless of the supply of power. Examples of a nonvolatile memory device include a read only memory (ROM), a mask ROM (MROM), a programmable ROM (PROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a phase change random access memory (PCRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), and a ferroelectric RAM (FRAM). A flash memory device may be a NOR-type memory device or a NAND-type memory device.
Among the memory devices, the PCRAM has a limited write endurance. The write endurance may be defined as the number of write (i.e., program) cycles that can be applied to a memory region before the storage medium of the device loses its reliability. Consequently, the life of a memory device may be reduced when write operations are concentrated on a specific memory region. In order to prevent this, the write operations performed on the memory region are counted, and data of a memory region which are frequently used and data of the memory region which are not frequently used are exchanged so that the entire memory region of the memory device can be used evenly.
Also, because of the continued increase in the degree of integration of memory devices, the interval between adjacent memory cells in the memory device has been reduced, which may result in malfunction due to an increase of a coupling effect between the adjacent memory cells. For example, a disturbance phenomenon, where data of a memory cell on which a write operation is performed as well as data of memory cells adjacent to the memory cell are corrupted due to heat generated during the write operation, may occur. To prevent this phenomenon, the write operations performed on the memory region may be counted, and data of the memory region which is frequently used may be restored through a scrubbing operation using an error correction code (ECC).